Charm Leptonic and Semileptonic Decays

Experimental results for the pseudoscalar decay constants f_{D} and f_{D_s} are reviewed. Semileptonic form factor results from D -> (pseudoscalar) l nu and D -> (vector) l nu decays are also reviewed.Comment: 8 pages, 4 figures, presented at the 11th International Conference on B-Physics at Hadron Machines (BEAUTY 2006) Sept. 25-29, Oxford, England; corrected typo

Study of plasmon resonance in a gold nanorod with an LC circuit model

Gold nanorod has generated great research interest due to its tunable longitudinal plasmon resonance. However, little progress has been made in the understanding of the effect. A major reason is that, except for metallic spheres and ellipsoids, the interaction between light and nanoparticles is generally insoluble. In this paper, a new scheme has been proposed to study the plasmon resonance of gold nanorod, in which the nanorod is modeled as an LC circuit with an inductance and a capacitance. The obtained resonance wavelength is dependent on not only aspect ratio but also rod radius, suggesting the importance of self-inductance and the breakdown of linear scaling. Moreover, the cross sections for light scattering and absorption have been deduced analytically, giving rise to a Lorentzian line-shape for the extinction spectrum. The result provides us with new insight into the phenomenon.Comment: 15 pages, 3 figure

Understanding stigma as a barrier to accessing cancer treatment in South Africa: implications for public health campaigns

Introduction: Cancer contributes to significant illness burden in South Africa, with delayed diagnosis resulting from limited knowledge of cancer, lack of biomedical treatment and stigma. This study examines ways in which people are identified as having cancer through perspectives of traditional healing or the biomedical model. Additionally, we sought to understand the stigma associated with cancer, including stereotypes, anticipated discrimination and coping styles. Methods: Livestrong Foundation conducted 11 semi-structured focus groups with key community stakeholders in three South African townships. Interviews examined the negative consequences of being labeled with a cancer diagnosis as well as causes of, possible prevention of and barriers and methods to improve access to cancer treatment. Analyses were completed using directed content analysis. Results: Revealed three main labeling mechanisms: physical appearance of perceived signs/symptoms of cancer, diagnosis by a traditional healer, or a biomedical diagnosis by a Western physician. Being labeled led to anticipated discrimination in response to prevalent cancer stereotypes. This contributed to delayed treatment, use of traditional healers instead of biomedical treatment and secrecy of symptoms and/or diagnosis. Further, perceptions of cancer were commonly conflated with HIV/TB owing to prior educational campaigns. Conclusion: Our study deepens the understanding of the cancer labeling process in South Africa and the resulting negative effects of stigma. Future anti-stigma interventions should partner with traditional healers due to their respected community status and consider how previous health interventions may significantly impact current understandings of illness

Creation and luminescence of size-selected gold nanorods

Fluorescent metal nanoparticles have attracted great interest in recent years for their unique properties and potential applications. Their optical behaviour depends not only on size but also on shape, and will only be useful if the morphology is stable. In this work, we produce stable size-selected gold nanorods (aspect ratio 1-2) using a size-selected cluster source and correlate their luminescence behaviour with the particle shape. Thermodynamic modelling is used to predict the preferred aspect ratio of 1.5, in agreement with the observations, and confirms that the double-icosahedron observed in experiments is significantly lower in energy than the alternatives. Using these samples a fluorescence lifetime imaging microscopy study observed two photon luminescence from nanoparticle arrays and a fast decay process (<100 ps luminescence lifetime), which are similar to those found from ligand stabilized gold nanorods under the same measurement conditions, indicating that a surface plasmon enhanced two-photon excitation process is still active at these small sizes. By further reducing the nanoparticle size, this approach has the potential to investigate size-dependent luminescence behaviour at smaller sizes than has been possible before

Inventory study of an early pandemic COVID- 19 cohort in South-Eastern Sweden, focusing on neurological manifestations

Background Neurological manifestations in patients with COVID-19 have been reported previously as outcomes of the infection. The purpose of current study was to investigate the occurrence of neurological signs and symptoms in COVID-19 patients, in the county of 6sterg\uf6tland in southeastern Sweden. Methods This is a retrospective, observational cohort study. Data were collected between March 2020 and June 2020. Information was extracted from medical records by a trained research assistant and physician and all data were validated by a senior neurologist. Results Seventy-four percent of patients developed at least one neurological symptom during the acute phase of the infection. Headache (43%) was the most common neurological symptom, followed by anosmia and/or ageusia (33%), confusion (28%), hallucinations (17%), dizziness (16%), sleep disorders in terms of insomnia and OSAS (Obstructive Sleep Apnea) (9%), myopathy and neuropathy (8%) and numbness and tingling (5%). Patients treated in the ICU had a higher male presentation (73%). Several risk factors in terms of co-morbidities, were identified. Hypertension (54.5%), depression and anxiety (51%), sleep disorders in terms of insomnia and OSAS (30%), cardiovascular morbidity (28%), autoimmune diseases (25%), chronic lung diseases (24%) and diabetes mellitus type 2 (23%) founded as possible risk factors. Conclusion Neurological symptoms were found in the vast majority (74%) of the patients. Accordingly, attention to neurological, mental and sleep disturbances is warranted with involvement of neurological expertise, in order to avoid further complications and long-term neurological effect of COVID-19. Furthermore, risk factors for more severe COVID-19, in terms of possible co-morbidities that identified in this study should get appropriate attention to optimizing treatment strategies in COVID-19 patients

Tunable variation of optical properties of polymer capped gold nanoparticles

Optical properties of polymer capped gold nanoparticles of various sizes (diameter 3-6 nm) have been studied. We present a new scheme to extract size dependent variation of total dielectric function of gold nanoparticles from measured UV-Vis absorption data. The new scheme can also be used, in principle, for other related systems as well. We show how quantum effect, surface atomic co - ordination and polymer - nanoparticle interface morphology leads to a systematic variation in inter band part of the dielectric function of gold nanoparticles, obtained from the analysis using our new scheme. Careful analysis enables identification of the possible changes to the electronic band structure in such nanoparticles.Comment: 13 pages,7 figures, 1 tabl

Role of commensurate and incommensurate low-energy excitations in the paramagnetic to hidden-order transition of URu2_2Si2_2

We report low-energy inelastic neutron scattering data of the paramagnetic (PM) to hidden-order (HO) phase transition at $T_0=17.5\,{\rm K}$ in URu$_2$Si$_2$. While confirming previous results for the HO and PM phases, our data reveal a pronounced wavevector dependence of low-energy excitations across the phase transition. To analyze the energy scans we employ a damped harmonic oscillator model containing a fit parameter $1/\Gamma$ which is expected to diverge at a second-order phase transition. Counter to expectations the excitations at $\vec{Q}_1=(1.44,0,0)$ show an abrupt step-like suppression of $1/\Gamma$ below $T_0$, whereas excitations at $\vec{Q}_0=(1,0,0)$, associated with large-moment antiferromagnetism (LMAF) under pressure, show an enhancement and a pronounced peak of $1/\Gamma$ at $T_0$. Therefore, at the critical HO temperature $T_0$, LMAF fluctuations become nearly critical as well. This is the behavior expected of a super-vector order parameter with nearly degenerate components for the HO and LMAF leading to nearly isotropic fluctuations in the combined order-parameter space.Comment: 6 pages; v3 accepted journal version; minor modifications compared to v

Measurement of the branching ratio of the decay D^0 -> \pi^-\mu^+\nu relative to D^0 -> K^-\mu^+\nu

We present a new measurement of the branching ratio of the Cabibbo suppressed decay D^0\to \pi^-\mu^+\nu relative to the Cabibbo favored decay D^0\to K^-\mu^+\nu and an improved measurement of the ratio |\frac{f_+^{\pi}(0)}{f_+^{K}(0)}|. Our results are 0.074 \pm 0.008 \pm 0.007 for the branching ratio and 0.85 \pm 0.04 \pm 0.04 \pm 0.01 for the form factor ratio, respectively.Comment: 13pages, 3 figure

Anti-inflammatory nuclear receptor superfamily in multiple sclerosis patients from Sardinia and Sweden

Several nuclear hormone receptors have been associated with inflammatory reactions. Particularly, liver X receptors (LXRs) have recently been identified as key transcriptional regulators of genes involved in lipid homeostasis and inflammation. LXRs are negative regulators of macrophage inflammatory gene expression. Multiple sclerosis (MS), a demyelinating disease of the central nervous system of unknown cause, is characterized by recurrent inflammation involving macrophages and their inflammatory mediators. Sweden belongs to the countries with a high MS incidence. In Italy, the MS incidence is lower, except on the island of Sardinia where the incidence is even higher than in Sweden. Subjects from Sardinia are ethnically more homogeneous, and differ from Swedes also regarding genetic background and environment. We studied mRNA expression of several nuclear hormone receptors in blood mononuclear cells (MNC) from female patients with untreated relapsing-remitting MS from Sassari, Sardinia, and Stockholm, Sweden. Sex- and age-matched healthy controls (HC) were from both areas. mRNA expression was evaluated by quantitative real-time PCR. We found altered mRNA expression of LXRs, estrogen receptors (ERs), and androgen receptor (AR) in MS. mRNA expression of both LXRα and LXRβ is lower in MS from Stockholm but not from Sassari. In particular, LXRα mRNA expression was significantly lower in MS from Stockholm as compared with all groups in the study including MS from Sassari. Low levels of ERα mRNA are seen in MS from both Stockholm and Sassari. The splice variant ERβcx showed significantly higher mRNA expression in MS from Sassari and Stockholm as compared with corresponding HC. In particular, ERβcx mRNA in MS from Sassari was remarkably higher as compared with all other groups in the study. Higher levels of AR mRNA are present in HC from Sassari. The findings indicate that the expression levels of anti-inflammatory nuclear receptor superfamily genes in MS appear to reflect both ethnic and environmental influences

A Comparison of Two Open Source LiDAR Surface Classification Algorithms

With the progression of LiDAR (Light Detection and Ranging) towards a mainstream resource management tool, it has become necessary to understand how best to process and analyze the data. While most ground surface identification algorithms remain proprietary and have high purchase costs; a few are openly available, free to use, and are supported by published results. Two of the latter are the multiscale curvature classification and the Boise Center Aerospace Laboratory LiDAR (BCAL) algorithms. This study investigated the accuracy of these two algorithms (and a combination of the two) to create a digital terrain model from a raw LiDAR point cloud in a semi-arid landscape. Accuracy of each algorithm was assessed via comparison with \u3e7,000 high precision survey points stratified across six different cover types. The overall performance of both algorithms differed by only 2%; however, within specific cover types significant differences were observed in accuracy. The results highlight the accuracy of both algorithms across a variety of vegetation types, and ultimately suggest specific scenarios where one approach may outperform the other. Each algorithm produced similar results except in the ceanothus and conifer cover types where BCAL produced lower errors